100% cotton rug warp from Dorr Mills is my favourite backing for hooking! It holds like linen, is soft on the hands, and has a nice even weave.
11 x 13 threads per square inch.
It does like to fray, so I have serged all the edges for you on any of the smaller pieces (The edges are not serged when purchased by the yard)
I can cut custom sizes as well, just let me know what you need!